The explosive growth of public and private information networks has revolutionized the way information is stored, accessed and used. The Internet, in particular, holds promise of becoming the ultimate publishing medium and repository for all kinds of information and electronic content.
Information products or electronically published materials are typically distributed in a digital form and recreated on a computer-based system having the capability to recreate (read, display or playback) the electronic content. Information products include books, multimedia works, audio and video recordings, and software. Electronic content offers some inherent advantages over traditional mediums of representation, such as:                a) Electronic content does not have physical weight. However, it needs to be stored on physical media or computer hardware having storage and/or memory capabilities.        b) Multiple copies of a published work need not be stored separately, for mass distribution, and can be generated upon demand.        c) The costs of duplication, reproduction, dissemination and distribution of electronic property or content are considerably reduced compared to traditional methods of printing, publishing and recording.        d) No loss of fidelity or deterioration in quality of display or playback across generations of copies. Almost impossible to differentiate a digital copy from a digital original.        
The fact that Intellectual Property (IP) can be embodied in forms which can be copied while owner retains the original, and, the increasing ease with which IP can be represented and stored electronically and distributed in mass quantities, are issues of great concern for content creators and distributors of intellectual property. The inherent advantages and characteristics of electronic content that has been stored in a digital format also pose some formidable challenges in safeguarding the Intellectual Property (IP) rights and other interests of creators, authors and publishers of electronic content. These concerns and challenges primarily arise as electronically stored data can be perfectly reproduced, duplicated and disseminated without payment of due consideration to the content providers, authors or publishers. Also, as digital content can be replicated without a loss in quality from the original, it becomes difficult if not impossible to distinguish between a digital original and a digital copy.
Any unauthorized distribution of electronic content results in loss of revenue to the content provider or publisher and an unpaid royalty to the author or creator. A wide spread practice of unauthorized copying and distributing of electronic content results in a substantial loss of revenue to the content providers as well as authors and creators. A wide spread duplication and unauthorized dissemination of intellectual content through a widely used public medium, such as the Internet, in fact jeopardizes enforceability of the Intellectual Property (IP) ownership rights of the content creators, authors, artists, publishers, studios and content providers across a wide spectrum of industries.
Thus, despite the advantages of digital content in terms of retrieving, accessing and disseminating, representing content or IP in a digital form is not an end in itself, it can only serve the broad interests when the digital representation does not undermine or otherwise dilute the time-limited monopoly granted to the authors or creators of the content by the US Constitution which empowers the law-makers “to promote the progress of science and the useful arts by securing to authors and inventors for limited times exclusive rights in their respective writings and discoveries.”
The problems associated with distributing electronic content and deterring unauthorized and unaccounted distribution and usage of such content have been described in the prior art. An excellent review of technical mechanisms and other methods including business models, intended for protecting intellectual property (IP) in digital form, is provided in a published National Research Council Report (NRC), titled The Digital Dilemma: Intellectual Property in the Information Age (National Academy Press, Washington, D.C., 2000), authored by the Committee on Intellectual Property Rights and the Emerging Information Infrastructure, convened by the Computer Science and Telecommunications Board (CSTB). This NRC report, herein incorporated by reference, describes various techniques, methods and technologies that have been employed in the prior art for protecting and distributing electronic content.
Although, conventionally IP protection is typically conceived in legal and technical terms, the NRC report underscores the fact that business models can serve as effective means of making digital content available in new ways that can be an effective deterrent to illegitimate uses of IP.
The business models for addressing IP are important due to the long history of dissemination of ideas, information and IP works through public or private sale of information products which enabled the content creators and publishers to be adequately rewarded for their involvement in creative pursuits and the dissemination process. The economic rewards to the content creators and distributors provided the incentive for continuation of the innovation cycle and fostering further creation of new ideas and information products. The dissemination process customarily builds upon a host of independent purchase decisions made by numerous people for purchasing information product(s). Information stored or represented by conventional methods is usually attached to an artifact such as a book, a tape, a cassette or a CD. In order to pass along the information the owner has to loan the artifact to another individual, however, once represented in digital form information can be readily copied and distributed. Digital IP, in a non-protected form, which can be readily passed along while the owner retains the original does not provide a commercial incentive for distributing the same.
Another disincentive for dissemination of digital information is that access is all or nothing. Even when access is provided for examination purposes the same information can be copied and distributed without rewarding the publisher or the creator. Commercial distribution of information without thwarting the economic interests of its creators and publishers is necessary for preserving a vital public domain of ideas, information and creative works for promoting the sciences, arts, humanities and ongoing technological innovation. The difficulty of protecting content that the distributor is trying to seek buyers for is described in the prior art. The following quote from the NRC report illustrates this well—“ . . . in the commercial context, overly stringent protection is as bad as inadequate protection: In either extreme—no protection or complete protection (i.e., making content inaccessible)—revenues are zero. Revenues climb with movement away from the extremes; the difficult empirical task is finding the right balance.”
How can then a distributor offer an information product for sale or invite a customer for a purchase evaluation when the content once shared can be freely distributed or copied? This is one of the questions that the present invention is directed at answering.
A principal technology that has been used for managing IP and the rights of content creators and distributors is cryptography. Cryptography or “encryption” involves scrambling or “encrypting” digital content and rendering it unusable until a legitimate party can unscramble or “decrypt” it. Encryption facilitates IP management by protecting content against disclosure or modification during transmission and while it is stored. If content is encrypted effectively, copying the files is nearly useless because there is no access to the content without the decryption key.
In “symmetric-key” encryption, the same key is used for both encrypting and decrypting. Information products, such as movies, songs, books, art and similar works can be distributed in an encrypted form while the decrypting key is only provided to authorized users (e.g. paying customers). This technique of distributing content, in a protected form, is customarily employed in cable television with pay-per-view programming where the decrypting key is provided to the paying customers utilizing special hardware (set-top cable box). The encrypted program can be safely broadcast without fear of unauthorized access due to decryption procedure required for viewing the specific pay-per-view programming.
In public-key cryptography, two different keys or “key-pairs” are used—a public key and a private key. Any message encrypted with the public key cannot be decrypted by using the same public key and requires a corresponding private key to decrypt it. Private keys are kept private by individuals, while public keys are made widely available or published. Secret messages intended for the recipient can be encrypted using the recipient public key. Once the message is encrypted, only the recipient, who knows the corresponding private key, can decrypt the message. Software is widely available to generate key pairs that have this property.
A combination of symmetric key and public-key encryption schemes is also used wherein symmetric-key encryption is used to encrypt the message, and then public-key encryption is used to transmit the decryption key to the recipient. Other applications of public key encryption are “digital signatures” and “identity certificates.” Digital signatures involve a private signing key.
In the prior art, copy protection and access control schemes rely principally on software-based encryption, hardware keys or a combination thereof. In terms of specific controls these techniques work by:                1. Restricting a user to make additional copies.        2. Requiring special purpose hardware to limit access to digital information.        3. Anchoring content to a single machine.        4. Packaging content in an encrypted container.        5. Attaching usage rights to the content via XML tags.        6. Fingerprinting and Watermarking.        
Software-based encryption techniques prevent conventional copying programs from making unauthorized usable copies. Generally, in these protection techniques, the execution of programs or information stored on a storage medium involves the presence of decryption key for display or execution of data. U.S. Pat. No. 5,027,396 ('396) describes a technique for execution protection of a floppy disk using an encrypted password located at an arbitrary location within the data. Other examples of prior art teachings discussed and referred to in '396, incorporated herein by reference, are directed towards copy-protecting disks or storage media in general see for e.g. U.S. Pat. Nos. 4,577,289; 4,462,078; 4,584,641; 4,734,796; 4,785,361; 4,849,836.
In the prior art a technique for restricting access and use of digital information to a particular machine or “anchoring” content to a single machine is described in U.S. Pat. No. 4,817,140 assigned to IBM. This technique is also referred to as hardware based authorization. U.S. Pat. No. 4,732,284 describes a hardware authentication utilizing public-key encryption techniques. Other examples of secure communication systems utilizing encryption or controlled distribution are described in U.S. Pat. Nos. 4,888,800 and 4,999,806.
Combinations of software based method and hardware key are described in U.S. Pat. Nos. 4,866,769 and 4,903,296. A method for preventing copying of a video program is described U.S. Pat. No. 4,907,093. A method of preventing unauthorized duplication of information from one storage medium to another and further restricting the use of information to one or more designated devices is described in U.S. Pat. No. 5,412,718.
U.S. Pat. No. 5,513,260 describes a method and apparatus for copyright protection of various recording media such as compact discs (CDs) utilizing a combination of symmetrical and asymmetrical data encryption to permit the player to handle either copy-protected or non-copy-protected media.
A method for invoking business operations and encouraging purchase of executable and non-executable software for distribution of digital information is disclosed in U.S. Pat. No. 5,509,070. This method requires the user to obtain an ID unique to the user for obtaining access to the advanced features.
Another method of protecting digital information particularly software is making the software product available for a pre-determined and limited time period such that the program is rendered unusable after the expiry of the allowed time-period. Methods and apparatuses for enabling trial period use of software products are covered under U.S. Pat. Nos. 5,563,946, 5,598,470, 5,689,560 and 5,737,416. A limited trial period can be effective for software products; however, it does not provide a solid business model for delivering other digital content such as books, music and movies due to several reasons. Firstly, even a singular use of the content is disincentive enough for paying or purchasing and secondly, once access is provided in a decrypted form it can be readily stored, displayed and distributed after the trial period has expired.
A method and apparatus to create, distribute, sell and control access to digital documents using secure cryptographic envelopes is described in U.S. Pat. No. 5,673,316 assigned to IBM Corporation. This technology has been commercialized under the IBM's trademark CRYPTOLOPE. Cryptolope objects are used for secure, protected delivery of digital content. Cryptographic envelopes can be compared to the other major technical approach to the same problem, secure servers. A cryptolope is a self-contained and self-protecting object and may include a variety of content types including text, images and audio. It can be delivered across a network or placed on a CD-ROM or other storage media and ties the usage conditions (for e.g. price) to the content itself. Commercial information and detailed description of the cryptolope technology can be obtained from the IBM website using the link—http://www.ibm.com/software/security/cryptolope/about.html
Other technologies for controlling and distributing electronic content have been developed by Content Guard, Inc. and Xerox Corporation (http:://www.contentguard.com) and have been described in U.S. patent Nos. listed below and herein included by reference—                “Interactive Contents Revealing Storage Device” (U.S. Pat. No. 5,530,235);        “System for Controlling the Distribution and Use of Digital Works” (U.S. Pat. No. 5,629,980);        “System for Controlling the Distribution and Use of Digital Works Having a Free Reporting Mechanism” (U.S. Pat. No. 5,634,012);        “System for Controlling the Distribution and Use of Composite Digital Works” (U.S. Pat. No. 5,638,443);        “System for Controlling the Distribution and Use of Digital Work Having Attached Usage Rights Where the Usage Rights are defined by a Usage Rights Grammar” (U.S. Pat. No. 5,715,403);        “System for Controlling the Distribution and Use of Rendered Digital Works through Watermarking” (U.S. Pat. No. 6,233,684)        “System for Controlling the Distribution and Use of Digital Works Using Digital Tickets.” (U.S. Pat. No. 6,236,971);        
Technologies to manage, secure, control and automate the flow of content and the access to services over a network are frequently referred to Digital Rights Management (DRM) Technologies. Content Guard is a provider of Digital Rights Management (DRM) technologies through XrML, extensible Rights Markup Language. XrML is a language to specify rights. XrML is an XML based usage grammar for specifying rights and conditions to control the access to digital content and services. Using XrML, the owners and distributors of digital resources (including content, services or software) can identify the parties allowed to use those resources, the rights available to those parties, and the terms and conditions under which rights may be exercised. Other uses of XrML and its application to development of business models for distributing digital content and services over a network or Internet are discussed in Content Guards's White Paper, “The Need for a Rights Language”, 2001 (also available on the web at: http://www.xrml.org/reference.asp).
A system for controlling access and distribution of digital property, herein included by reference, is disclosed in U.S. Pat. No. 5,933,498. In this prior art teaching access to protected portions of the data, in a useable form, is prevented. Access to the protected portions of the data is only provided in accordance with rules or access rights as enforced by a mechanism protected by a tamper detection feature.
Once again developing a common language for describing rights and rules for use, duplication and distribution of electronic content is useful in a business context, however, the mechanisms of protection rely on encryption. In addition to encryption, other techniques for protecting digital content include “watermarking and “fingerprinting” The use of watermarks for the purpose of identifying the manufacturer and quality of a paper discreetly is well known. Watermarking techniques have also been employed for preventing forgery of banknotes and checks (see for e.g. U.S. Pat. Nos. 5,122,754 and 5,538,290).
Analogous to paper making digital watermarks can be used to mark each individual copy of a digitized work with information identifying the title, copyright holder, and even the licensed owner of a particular copy. A method and system for digital watermarking is described in U.S. Pat. No. 5,905,800 herein incorporated in its entirety by reference. A method for applying a digital watermark to a content signal is disclosed. The method includes identifying a binary sequence watermarking key and applying the binary sequence to the content signal. The digital watermark is then encoded within the content signal at one or more locations determined by the watermarking key.
Another prior art teaching U.S. Pat. No. 5,195,135 discloses a method and apparatus for the automatic censorship of audio-video programming at the receiver in accordance with a viewer-selected censorship mode and classification data encoded in the audio-video programming signal. The censorship classification data comprise codes that classify the programming for several different subjects and several different censorship levels. Censorship of the audio-video programming is accomplished by automatically obscuring the audio and/or video signal by blurring the audio or video frame.
U.S. Pat. No. 6,216,228, herein incorporated in its entirety by reference, describes a method and a system for automatically controlling display of video or image data in accordance with content classification information embedded in the form of digital watermarks. A controller decodes the watermarked content codes and then prevents displaying of certain material, by overlaying the display with blanking data, if the codes match certain stored codes, which the controller has been set to respond to. The use of invisible digital watermark codes by a controller, which operates in response to the watermark codes, provides reliable control since the codes are more difficult for unauthorized persons to detect and remove than other embedded codes would be. U.S. Pat. No. 6,216,228 is directed towards censorship and screening of sensitive, adult and pornographic content. Other U.S. patents that disclose similar parental control features include for example, U.S. Pat. Nos. 4,930,158; 4,930,160; 5,253,066 and 5,387,942.
Digital watermarks are applied in a variety of ways and for a variety of purposes. Watermarks can vary according to the type of content they are affixed to: text, images, audio or video. Watermarks may be visible or imperceptible to the user. The embedded watermark may be a text, image, signal or a code. Typically watermarks contain information about the provider or publisher. The term fingerprinting is often used to connote marks that carry information about the end user and are essentially employed for tracing information about the user.
Typical uses of digital watermarking and fingerprinting are:                To confirm genuineness and integrity of the content.        To authenticate ownership of a digital work.        To introduce an electronic fingerprint for preventing or tracing piracy or unauthorized duplication.        To mark a digital work, when digital watermark is keeping additional information about the product itself such as time and date stamping of photographs.        For censorship of sensitive content.        
The practical applications of watermarking are not so much a deterrent for private copying as an aid to police wide scale commercial pirating of digital content.
Thus, as described herein above, prior art techniques of distributing digital content provide either “complete and open access” or “complete prevention of access”. In the former case the content has little commercial value since it is freely distributed, and in the latter case the consumer has to take the leap of faith prior to making a purchase decision. In other words, the techniques for protection against unauthorized use of digital content rely primarily on preventing access to the published work or allowing access to the published work only in an encrypted form and thereby not allowing the customer to preview, display or use the published work without paying for it. Thus, content protection technologies provide mechanisms for Protection of digital data or Rights Management for content creators and distributors; however, they do not necessarily facilitate the purchase decision process for the consumer. The consumer is only granted a very limited access to the preview material for determining if the content under evaluation is a worthwhile purchase.
FIGS. 1a and 1b show conceptual representations of the distribution models based on unrestricted and restricted access schemes respectively.
The unrestricted access scheme, shown in FIG. 1a, is referred to as “Open-Box Model” and denotes free or unrestricted access to the unencrypted content object. The content label on the box analogically describes the contents of the box by—an abstract of the content material or excerpts therefrom or preview of the underlying content. Due to readily available unrestricted access to the unencrypted content object the unencrypted content object has an insignificant commercial value.
The restricted access scheme, shown in FIG. 1b, is referred to as the “Closed-Box Model” and denotes restricted or conditional access to the encrypted content object. The restricted access model referred to as “closed box model” requires certain obligations to be met prior to release or decryption of the encrypted content object. It is worth noting that even if, unrestricted access can be provided to the encrypted content object, it would have little or no utility until it is decrypted.
Consistent with the above Closed-Box Model, the primary method of distribution of commercially valuable electronic or digital content is providing no access to the “content object” or “the body of the document or digital work” unless some form of payment has been received from the user. Generally, an abstract or a few excerpts of the published work are provided to the customer for making a purchase decision and the published work is released in its entirety only after payment has been received from the customer. For example, in offering a book or similar subject matter for sale which, has been published electronically, the content provider or publisher generally provides any one or more of the following items—excerpts from the book, a few chapters of the book, a brief description of the contents, the complete Table of Contents, and/or testimonials of other readers.
However, this method of controlling access to electronic content, prior to a commitment of purchase by the consumer, affects the quality of information available to the user or consumer for making a purchase decision. Thus, in the previous example, the electronic information received or previewed by the reader is of an inferior quality compared to that obtained by the reader during a physical trip to the local bookstore and actually examining the printed book, in its entirety, prior to its purchase.
Developing a system for providing a consumer with electronic content that—is substantially representative of the electronic publication or electronically published content, prior to its sale by the content provider or its purchase by the consumer; and that in addition, does not compromise the commercial value of the electronic content or publication (or render it worthless) offers several challenges:    a) Any attempt at increasing the relevancy between the preview material or “pre-sale electronic content made available for purchase decision” and the “post-sale published electronic content”, such that the former is substantially and truly representative of the latter, almost immediately compromises the value of the published electronic content or removes the necessity and the incentive or motivation for its purchase.    b) Relevancy between the “pre-sale electronic content made available for purchase decision” and the “post-sale published electronic content” is dependant on the type of electronic content. Thus, for instance, some relevancy may be attached to pre-sale and post-sale versions of a video recording wherein a muting effect has been applied to the pre-sale video version; applying the same muting effect to a song or an audio recording provides no relevancy at all. It will be recognized by those of ordinary skill that relevance is not absolute but is dependent on the knowledge, interest and motive of the user. A more knowledgeable user can determine relevancy quite readily, while a motivated buyer who for instance needs a textbook recommended by a course-instructor would make a purchase decision without the publisher-supplied information.    c) Other fundamental difficulties in dealing with electronic content are realized in the seemingly endless variety of formats and file structures for representing a given type of electronic content. Virtually, all information that can be represented by words, numbers, graphics, or system of commands and instructions can be formatted into electronic digital information but the final representation, display, or playback devices can vary by the type of data-handling capacity or the quality of output.    d) Electronic content is delivered by various mediums such as Television, Cable, Satellite Transmissions, and On-line services transmitted, over public and private networks including broad distributed network such as the Internet, via telephone lines or through wireless transmissions. The electronic content providers include media and software companies such as AOL Time Warner, Microsoft, Yahoo etc, local and long distance telephone companies such as AT&T, Verizon, Cable companies, Cellular telephone companies, E-mail services, etc. which by their very nature of their enterprises are competitively positioned and adopting a universal standard of content delivery is difficult if not impossible.
From the above, it can be readily established that there is a need for a system, which:                Provides an improved method for offering, displaying and distributing electronic content that provides adequate and relevant exposure to the published electronic content for potential purchase purposes;        Provides the consumer with an improved purchase decision framework regarding the electronically published materials;        Provides increased fidelity or relevance between before-sale and after-sale electronic content by allowing customers to preview the original published electronic content in a substantially deterministic way for making purchases;        Does not compromise the value of the for-sale electronic content by premature disclosure of for-sale electronic publication in its entirety or full-utility configuration.        
As will become clear from the ensuing detailed description, in its simplest form the present invention provides for a “Mask” or “Masking Effect” that is superposed on the original content as an “interruption”, “discontinuity” and/or “disorientation” with the sole-purpose of providing a preview of the underlying original content but in manner that only suffices for purchase-evaluation purposes and detracts from the wholesome utilization or enjoyment of the digital content. The masking effect is readily removed or removable, once customer meets the obligations or conditions for purchase of the content.
Superposition or overlays have been described in the prior art. A digital Image Overlay System and Method for overlaying one digital image on another digital image is described in U.S. Pat. No. 5,283,867. More particularly this method describes transferring and reformatting a block of image data from a bit-planar organized, source memory and overlaying it onto an image stored in a display target memory. This prior art teaching is particularly directed at image overlays in presentations and picture-to-picture transitions and does not teach a method of physically masking digital content for the purpose of distributing digital content.
A device for distribution of a digital music information object is described in U.S. Pat. No. 5,636,276. The digital music information object is composed of a core and a number of additional layers; wherein, the core includes an encryption table, for interacting with encryption and decryption modules of the system. The additional layers may include audio layer class, score layer class, text layer class and video layer class. Again, this prior art teaching does not describe a masking effect or a masking layer, which is removable at the time of purchase.
A system and method for providing annotation overlays from diverse sources of commentary for World-Wide Web document is disclosed in U.S. Pat. No. 5,826,025. Again, this prior art teaching does not discuss removable masking or overlays as a part of the distribution process.
In the present invention, the problems associated with free, open and uncompensated distribution of electronic content to users or consumers without thwarting the motivation for subsequent purchase are addressed. A system is provided for distributing information or products thereof in a fashion which supports both modes—a payment based mode which makes the electronic content available for paying users and a non-payment based mode for providing content to users for previewing and making a purchase decision.